CVE-2026-20271
HighCVSS 8.6Exploitation Probability (EPSS)
Low risk19th percentile - higher than 19% of all known CVEs
Summary
A vulnerability in Cisco IOS XE Software related to insufficient control flow management (CWE-691), discovered during an internal security review. It is addressed in software hardening releases.
Risk Assessment
The vulnerability could allow an attacker to manipulate control flow, potentially leading to unexpected behavior or device failure.
Recommendation
Install the latest Cisco IOS XE hardening release that includes fixes for this vulnerability.
Other vulnerabilities in Cisco IOS XE Software
See all- CVE-2026-20272Critical
As part of an internal security review in Cisco IOS XE Software, multiple vulnerabilities related to improper neutralization of special elements (CWE-74) were discovered. Hardened software releases addressing these issues have been issued.
- CVE-2026-20267Critical
As part of an internal security review in Cisco IOS XE Software, multiple vulnerabilities related to improper access control (CWE-284) were discovered. Hardened software releases addressing these issues have been issued.
- CVE-2017-12229Critical
A vulnerability in the web-based user interface (web UI) of Cisco IOS XE 3.1 through 16.5 allows an unauthenticated remote attacker to bypass authentication to the REST API. The issue is due to insufficient input validation for the REST API.
- CVE-2026-20311Medium
A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This is due to insufficient error handling in the web-based management interface. An attacker could exploit this by authenticating with a malformed certificate, potentially causing the device to reload.
- CVE-2026-20308Medium
A vulnerability in the web-based management interface of Cisco IOS XE Software allows an authenticated remote attacker with low privileges to perform a DoS attack. The issue is due to insufficient input validation, and exploitation can make the interface unresponsive.
- CVE-2026-20273High
A vulnerability in Cisco IOS XE Software related to improper input validation (CWE-20), discovered during an internal security review. It is addressed in a software hardening release.
- CVE-2026-20270High
A vulnerability in Cisco IOS XE Software related to incorrect calculation issues (CWE-682), discovered during an internal security review. It is addressed in software hardening releases.
- CVE-2026-20269High
A vulnerability in Cisco IOS XE Software related to improper control of a resource through its lifetime (CWE-664), discovered during an internal security review. It is addressed in software hardening releases.
- CVE-2026-20268High
A vulnerability in Cisco IOS XE Software related to improper restriction of operations within the bounds of a memory buffer (CWE-119), discovered during an internal security review. It is addressed in software hardening releases.
- CVE-2026-20263High
A vulnerability in the BEEP feature of Cisco IOS XE Software allows an unauthenticated remote attacker to cause a denial of service (DoS) by sending a specific BEEP SOAP request. The issue is due to improper handling during parsing.
Original NVD description (English source)
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20271 are related to insufficient control flow management issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-691.